In System Safety FAQs I will deal with the most commonly searched-for online queries. This post is also the basis for the First in a new series of monthly webinars I’m running. I will also be answering your questions: leave them in the comments at the bottom of this post!
What is System Safety?
This definition from NASA is spot on. System Safety is fundamentally about reducing the risks of mishaps (accidents). The NASA Office of Safety and Mission Assurance website is great for practitioners!
This Wikipedia article reminds us that safety risk management is a subset of risk management in general. It also brings in the concept of a ‘hazard’, which is typical for ‘system safety’ – see my free lesson on basic risk concepts for more information.
Where Does Safety Start?
Safety is an ‘emergent property’, that is it comes about by pulling together many different things. Only leaders and managers can deliver these things; it doesn’t work if you try to do it from the bottom up.
I would also say that safety begins at the start of the lifecycle with requirements – see my short video about what System Safety is:
Safe System Approach?
This is a great view of a safe system approach, or strategy, from the world of road safety. Road networks, their commercial and private users, neighbors, regulators, emergency services, etc., form a very complex distributed system.
Why System Safety?
What are the benefits?
I would add that a systematic approach to safety saves time and money in the long run.
System Safety for The 21st Century
Traditional System Safety has its critics, most famously professors Nancy Leveson and Erik Hollnagel. They have made various criticisms of system safety – some of which I agree with, and some I most definitely do not.
Leveson has proposed new methods:
- System-Theoretic Accident Model and Processes (STAMP);
- Systems Theoretic Process Analysis (STPA); and
- Causal Analysis using System Theory (CAST) – accident analysis.
Hollnagel has written on a wide variety of safety topics including cognition, organizational robustness, and resilience. He also coined the terms “Safety I” for traditional safety approaches, and “Safety II” to describe the conceptual approach that he and others have developed.
He designed the Functional Resonance Analysis Method (FRAM).
I have tried FRAM, and even without any training (which is recommended), I found it tremendously powerful. FRAM can analyse problems that conventional safety techniques just can’t get to grips with.
Others have also introduced the term “Safety III”, but I’m not sure how useful these labels are. Perhaps we are now on a trajectory of diminishing returns.
System Safety is a Design Parameter
To save us from all this abstract navel-gazing, let’s get back to practical matters.
Concrete, specific, practical: I love it! Let’s not forget that we do safety for a reason, and big part of that is to control the machines that make our modern world. This doesn’t sound very exciting, but automation has enabled huge increases in productivity, wealth, health, quality of life, lifespan and human rights. Let’s remember that during the current hysteria about Artificial Intelligence (actually Machine Learning).
Safety System of Work
If we think about it, this ties in nicely with the definition of a system used in system safety, e.g.:
System Safety in Engineering
There are a number of ways that we could answer this (implicit) question. Here’s one from the Office of The Under Secretary Of Defense For Research And Engineering:
This definition neatly pulls together activities, hazards and accidents, those impacted and the aim of the whole thing. Phew!
I’m going to be talking about these topics in more depth in a webinar on EventBrite. There are only 25 tickets, which are worth getting for all the extras! If you don’t get in, then join my email list to get an invitation.
Questions and Comments?
Please leave them below.
Meet the Author
My name’s Simon Di Nucci. I’m a practicing system safety engineer, and I have been, for the last 25 years; I’ve worked in all kinds of domains, aircraft, ships, submarines, sensors, and command and control systems, and some work on rail air traffic management systems, and lots of software safety. So, I’ve done a lot of different things!